It's been about 100 days into the presidency of Rodrigo Duterte.

Since he took power, the Philippine president has overseen the killing of more than 3,500 people in his war on drugs, offended world leaders and strained relations with the US.

In an exclusive first interview since he was sworn in, we talk to Duterte about his controversial war on drugs and foreign policy - including deteriorating relations with the United States and potentially warming relations with China.

"We have three million drug addicts, and it's growing. So if we do not interdict this problem, the next generation will be having a serious problem ... You destroy my country, I'll kill you. And it's a legitimate thing. If you destroy our young children, I will kill you. That is a very correct statement. There is nothing wrong in trying to preserve the interest of the next generation."

We have three million drug addicts, and it's growing. So if we do not interdict this problem, the next generation will be having a serious problem ... You destroy my country, I'll kill you. And it's a legitimate thing. If you destroy our young children, I will kill you. That is a very correct statement. There is nothing wrong in trying to preserve the interest of the next generation."

But Duterte admits that children and innocent people have also been killed in the bloody crackdown, and promises to investigate these extrajudicial killings, but he also calls them "collateral damage".

When asked about the contested South China Sea, Duterte says:

"We will not give up anything there; it's an entitlement ... You can only negotiate to prevent a war ... They invited me for talks, and I will go."